Such satellite active antenna systems need to be of ever-increasing complexity in terms specifically of the number of beams (m) handled by a single radiating panel (of n radiating elements). The complexity and the missions of the beam distributor are thus increased, since it becomes necessary firstly to provide power division from m.times.1 to m.times.n, and secondly to provide recombination from m.times.n to 1.times.n:
routing then becomes more dense and thus more difficult, particularly when providing identical electrical path lengths for all of the signals; losses increase inevitably; and PA1 the presence of a plurality of beams make it necessary for the illumination law of each pencil in terms of amplitude and phase to be handled within the distributor itself, between the division and recombination functions, which makes it essential to integrate chips (attenuator, phase shifter) within the distributor. PA1 when the operating frequency exceeds 20 GHz. Under such circumstances, the RF multilayer interconnection techniques usable in that technology (in particular plated-through holes (PTHs)) are limited by the present state of the art; and PA1 for chip integration within the distributor itself since the method of making multilayer PCBs (lamination, pressure, thermofusion) is generally incompatible with any component in relief that it is desired to insert in the multilayer structure. This drawback makes it necessary to offset the chips outside the distributor. PA1 Finally, distributors are built using a horizontal stacking model for the layers parallel to the plane of the antenna, which gives rise to major constraints on performance (generally narrow band) and the space occupied by the interconnections with the radiating elements which are then disposed perpendicularly to the distributor. PA1 Such interconnection can be provided only via the edges of the circuit, which constitutes a major drawback for a "horizontal" distributor: increased losses to take signals to the edges are unacceptable, and the routing density on the edges which offer very little room provides no simplification compared with other solutions. PA1 the forming layers extend substantially perpendicularly to the main plane of the antenna; PA1 the forming layers and the connection layers are assembled together by molding so that the beam distributor constitutes a single block; and PA1 the radiating elements are connected directly to the second connection means.
Finally, the inevitable increase in frequency makes the techniques and technologies that have traditionally been used less and less suitable for implementing active antenna distributors.
At present, so-called organic multilayer printed circuit board (PCB) technologies are those which are most suited to the beam distributor problem. Nevertheless, they turn out to be more or less inappropriate under certain conditions, such as: